Gamma-Radiation Damage in Epitaxial Gallium Arsenide

Abstract

Electrical and photoluminescence measurements were carried out on liquid epitaxial GaAs single crystals after irradiation at room temperature by 1.25-MeV 60Co γ rays. Following each of a series of irradiations, Hall measurements were made on both n- and p-type crystals as a function of temperature between 77 and 300°K. The n-type crystals exhibited energy levels 0.13, 0.16, and 0.30 eV below the conduction band minimum after irradiation. The 0.13- and 0.16-eV levels were introduced during irradiation at roughly one-half the rate at which compensating deep acceptors were introduced. The p-type crystals showed energy levels 0.059 and 0.10 eV above the valence band maximum. Before irradiation, these p-type crystals had energy levels in the lower 0.20 eV level of the band gap. It is, therefore, not possible to determine whether the 0.059 and 0.10 eV were produced by irradiation or were merely uncovered as the free-hole density was reduced by radiation-induced deep donors. The carrier removal rate at 77°K was 0.012 cm−1 for p-type crystals. Photoluminescence measurements on irradiated material revealed additional energy levels near the center of the band gap.

Micro-Raman and photoluminescence studies of neutron-irradiated gallium nitride epilayers

“…It is well known that irradiation of high-energy particles, such as neutrons and electrons, can induce structural defects in semiconductors. In the past few decades, there were many reports discussing the irradiation-induced defects in silicon, 7 GaAs, [8][9][10] GaP, 11 and InP. 12 However, only a few studies 13,14 have been reported on the effects of neutron irradiation on the microstructural and optical properties of GaN thin films.…”

“…19 Usually, carrier removal is mainly due to the trapping of majority carriers by structural defects. 8,9,21,22 To test this idea and to investigate the crystal structure of the irradiated GaN, PL spectra of the samples were taken. Figure 2 shows the low-temperature PL spectra of the samples.…”

Positron annihilation measurements in high-energy alpha-irradiated n-type Gallium Arsenide

“…Several studies on the annealing of radiation-induced defects in GaAs have shown the changes in the electrical properties of the material are due to the introduction of those defects [10][11][12][13][14]. Aukerman et al [10] showed the recovery of electron-induced defects in p-type GaAs samples to be qualitatively different from that in n-type GaAs samples.…”

Raman Scattering and X-Ray Diffraction Study of Neutron Irradiated GaN Epilayers

“…Usually, carrier removal is mainly due to the trapping of majority carriers by structural defects [8,9,20,21]. To test this idea and to investigate the crystal structure of the irradiated GaN, XRD scans of the samples were made.…”

“…It is well known that irradiation by high-energy particles such as neutrons and electrons can induce structural defects in semiconductors. In the past few decades, there have been many reports discussing the irradiation-induced defects in silicon [7], GaAs [8][9][10], GaP [11] and InP [12]. However, only a few studies [13,14] have reported on the effects of neutron irradiation on the microstructural and optical properties of GaN thin films.…”